Coaxial breakaway coupling with vapor assist check valve

ABSTRACT

A coaxial breakaway coupling and a coaxial hose connect a fuel dispensing pump to a coaxial fuel dispensing nozzle, and the coupling includes first and second tubular valve bodies releasably coupled together by an annular canted coil spring. Each valve body supports therein an axially movable tubular valve member for defining an inner vapor return passage and an outer fuel supply passage, and a vapor return check valve member is supported for axial movement within the vapor return passage upstream of an annular valve seat. All of the valve members are spring biased towards closed positions and move to open positions when the valve bodies are coupled together. When the valve bodies are uncoupled or separate in response to an axial breakaway force, the valve members close, and suction from a vacuum pump connected to the vapor return passage pulls the check valve member towards it closed position against the valve seat. In a modification, the breakaway coupling is integrated with a 45° coaxial swivel coupling connected to a coaxial fuel dispensing nozzle.

RELATED APPLICATION

This application is a division of application Ser. No. 08/286,507, filedAug. 5, 1994, U.S. Pat. No. 5,433,247.

BACKGROUND OF THE INVENTION

This invention relates to breakaway couplings for use with a coaxialfuel supply and vapor recovery hose and of the general type disclosed inU.S. Pat. No. 4,763,683 which issued to the assignee of the presentinvention. Other forms of such coaxial breakaway couplings are disclosedin U.S. Pat. No. 4,827,960 and U.S. Pat. No. 5,135,029. Such coaxialbreakaway couplings are commonly used to connect one end of a flexiblecoaxial hose to a fuel dispensing pump. The opposite end of the hose isconnected to a vapor recovery fuel dispensing nozzle, for example, ofthe type disclosed in U.S. Pat. No. 5,255,723 which also issued to theassignee of the present invention.

In one type of vapor recovery system, such as disclosed in U.S. Pat. No.5,255,723, the inner conduit of the flexible coaxial hose is used tosupply liquid fuel from the dispensing pump to the dispensing nozzle,and the annular passage defined between the inner conduit or tube andthe outer conduit or tube is used for returning vapor displaced by fuelin a motor vehicle tank back through the dispensing pump to theunderground fuel storage tank. In another type of vapor recovery systemthe inner conduit or tube within the coaxial hose is used for returningfuel vapor from the dispensing nozzle to the dispensing pump, and theannular outer passage surrounding the inner tube, is used for supplyingliquid fuel from the dispensing pump to the dispensing nozzle. Thissystem is commonly referred to as a vapor assist system since thedispensing pump housing encloses a vacuum pump for creating a suctionwithin the inner conduit or tube for sucking fuel vapors through thedispensing nozzle back to the dispensing pump.

When a breakaway coupling is used with a coaxial hose in a vapor assistrecovery system, it is desirable for the coupling to incorporate checkvalves in not only the annular fuel supply passage but also in thecenter vapor return passage. Thus in the event the sections of thecoupling are separated, both the fuel supply passage and the vaporreturn passage extending from the dispensing pump are closed so thatfuel does not exit, and air does not enter the vapor return passage.Such coaxial breakaway couplings for vapor assist recovery systems andwhich are reconnectable, are produced by Huskey Corporation and RichardsIndustries, Inc. and sold under the trademarks SAFE-T-BREAK andRICHARDS, respectively.

In some vapor assist recovery systems, the vapor return vacuum pumpenclosed within the housing of the dispensing pump creates a substantialsuction in the vapor return passage, for example, on the order of 5" Hg,and this suction continues after the sections of the breakaway couplinghave separated. Thus with the above coaxial breakaway couplings for thevapor recovery assists systems, it is necessary to use a compressionspring which exerts a substantial force for holding the valve within thevapor return passage closed after the breakaway coupling has separated.If the valve does not remain closed, air is sucked past the valve andthrough the vapor return passage, and the vapor recovery system becomessignificantly less effective,

SUMMARY OF THE INVENTION

The present invention is directed to an improved coaxial breakawaycoupling which is simple in construction and assembly and which preventsair from being sucked into the recovery system in the event there is abreakaway condition and the sections of the coupling separate. Thebreakaway coupling of the invention is also compact in design and, inaccordance with the modification of the invention, is integrated with acoaxial swivel coupling which attaches to a coaxial dispensing nozzle.

In accordance with one embodiment of the invention, a set of tubularvalve bodies are releasably connected by an annular canted coil spring.The spring connection permits the valve bodies to separate in responseto a predetermined tension force and also to be reconnected with asubstantially lower compression force. Each of the valve bodies supportsa concentric center support tube which slidably supports a tubular valvemember for axial movement. The tubular valve members and correspondingsupport tubes define therein a vapor return passage, and an annularliquid fuel supply passage is defined between the tubular valve membersand support tubes and the surrounding tubular valve bodies. The valvemembers carry external sealing rings for engaging corresponding taperedannular valve seats within the valve bodies when the bodies areseparated. The tubular valve members also have interfitting portionswhich move the valve members to open positions against correspondingcompression springs when the valve bodies are connected or coupledtogether.

The tubular valve member within the valve body connected to the fueldispensing pump includes an annular valve seat. A check valve member issupported for axial movement upstream of the valve seat within the vaporreturn passage and is moved to an open position when the tubular valvebodies and the tubular valve members are coupled together. When thevalve bodies are uncoupled in response to a predetermined tension force,the check valve member is moved by a compression spring against thevalve seat within the vapor return passage and is pulled against thevalve seat by the suction within the vapor return passage so that air isprevented from entering the vapor return passage after a breakaway. Inanother embodiment, the breakaway coupling of the invention isintegrated with a 45° coaxial swivel coupling which connects directly toa coaxial fuel dispensing nozzle.

Other features and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an axial section of a coaxial breakaway coupling constructedin accordance with the invention and shown in its coupled position;

FIG. 2 shows the coupling of FIG. 1 in its uncoupled position;

FIG. 3 is a radial section taken generally on the line 3--3 of FIG. 1;

FIG. 4 is a radial section taken generally on the line 4--4 of FIG. 2;

FIG. 5 is a radial section taken generally on the line 5--5 of FIG. 1;and

FIG. 6 is an axial section of a modified coaxial breakaway couplingsimilar to the coupling shown in FIG. 1 and integrated with a swivelcoupling in accordance with another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A coaxial breakaway coupling 10 includes interfitting sections 12 and 14which are primarily constructed of aluminum castings. Section 12includes a tubular valve body 16 which has one end portion 18 threadedinto a tubular fitting 21 having internal threads 22 for receiving thefitting (not shown) on one end of a coaxial fuel supply hose of thegeneral type disclosed in above mentioned U.S. Pat. No. 4,763,683. Aresilient O-ring 24 forms a fluid-tight seal between the tubular body 16and fitting 21, and an external groove is formed within the body 16 forreceiving a resilient O-ring 27. A tubular sleeve 32 surrounds the valvebody 16 and includes an inwardly projecting end flange 33 which isclamped between the fitting 21 and an external shoulder 34 on the valvebody 16. After the fitting 21 is tightened on the valve body 16, a setscrew 37 secures the assembled parts. As shown in FIG. 3, the sleeve 32has a cylindrical outer surface and a generally hexagonal inner surface39.

The tubular valve body 16 has an opposite reduced end portion 42 with anexternal circumferential groove 43, and the end portion 42 also has aninternal frusto-conical or tapered valve seat 46. A center support tube48 is positioned within the end portion 18 of the valve body 16 and hasan outwardly projecting flange 49 positioned within a counterbore withinthe fitting 21 and secured by a spring retaining ring 51. The flange 49has circumferentially spaced arcuate slots or passages 53 which definetherebetween three uniformally spaced ribs.

A tubular valve member 55 is supported by the tube 48 for axial movementwithin the tubular valve body 16 and has an enlarged portion with acircumferential groove for receiving a resilient O-ring 57. The O-ring57 forms a fluid-tight seal with the valve seat 46 in response to anaxial force produced by a compression spring 59 extending between oneend of the support tube 48 and an internal shoulder within the valvemember 55. A resilient O-ring 62 forms a fluid-tight sliding sealbetween the support tube 48 and tubular valve member 55, and anotherresilient O-ring 64 is carried within an internal groove formed withinthe inner end portion of the valve member 55.

The coupling section 14 of the coaxial coupling 10 includes a tubularvalve 66 which has a hexagonal outer surface 67 with rounded corners formating with the inner surface 39 of the sleeve 32, as shown in FIG. 3.The outer end portion of the valve body 66 has internal threads 69 forreceiving the fitting on one end of a short flexible coaxial hose (notshown) having an opposite end connected to the fuel dispensing pump. Thetubular valve body 66 also has a frusto-conical or tapered valve seat 71and an internal tapered groove 73 within a bore 74 which is sized toreceive the end portion 42 of the tubular valve body 16, as shown inFIG. 1.

An annular canted coil spring 76, for example, of the type disclosed inU.S. Pat. No. 4,655,462, is confined within the groove 73 and isexpanded slightly by the end portion 42 of the valve body 16 until thespring 76 snaps into the external groove 43 within the valve body 16, asshown in FIG. 1, when the coupling sections 12 and 14 are pressedaxially together to a connected or coupled position. The canted coilspring 76 and the tapered surfaces of the grooves 73 and 43 are selectedto provide for separation of the coupling sections 12 and 14 with apredetermined tension force and the recoupling of the sections with asubstantially lower axial or compression force.

A support tube 82 is supported concentrically within the valve body 66by a flange portion 84 seated within a counterbore within the valve body66 and secured by a spring retaining ring 87. The flange portion 84 hasperipherally spaced arcuate slots or passages 89 defined between threeuniformally spaced ribs which integrally connect the support tube 82 andflange 84. The inner end portion of the tube 84 has a peripheral groovefor receiving a resilient O-ring 92, and a hub 94 with three outwardlyprojecting and uniformally spaced ribs, is pressed into the inner endportion of the support tube 82. The ribs define three arcuate slots orpassages 97 between the ribs. The hub 94 receives the threaded endportion of an axially extending pin 99.

A tubular poppet valve member 110 is supported by the tube 82 for axialsliding movement and has an enlarged annular portion 112 with aperipheral groove receiving a resilient O-ring 113. A compression spring115 extends between the end and the support tube 82 and an internalannular shoulder within the valve member 110 and urges the valve memberand O-ring 113 against the tapered annular seat 71 within the valve body66. The compression spring 115 also retains an annular valve seat 118 inthe form of a resilient gasket and back-up washer engaging the spring.The gasket is pressed against an annular shoulder within the tubularvalve member 110.

A check valve member 120, having tapered opposite end portions, ispositioned concentrically within the enlarged portion 112 of the valvemember 110 and is urged against the annular seat 118 by a compressionspring 123 surrounding a cylindrical pin 126. The pin 126 and checkvalve 120 are supported for axial movement as a unit by a hub member 128having three outwardly projecting and circumferentially spaced ribswhich are pressed into the inner cylindrical end portion of the tubularvalve member 110.

When the coupler sections 12 and 14 are snapped together in the coupledposition shown in FIG. 1, the support tubes 48 and 82 and the tubularpoppet valve members 55 and 110 define a vapor return passage 135 inwhich the fuel vapor flows from left to right in FIG. 1 to a vacuum pump(not shown) located within the housing of a fuel dispensing pump. Liquidfuel is supplied from the dispensing pump through the coupler from rightto left in FIG. 1 through an annular passage 138 defined within thetubular valve bodies 16 and 66 and around the inner support tubes 48 and82 and tubular valve members 55 and 110.

When the coupling sections 12 and 14 are assembled together, as shown inFIG. 1, the interfitting connection of the tubular valve members 55 and110 moves the valve members to their retracted open positions so thatliquid fuel is free to flow through the coupling within the annularpassage 138. As also shown in FIG. 1, when the coupler sections 12 and14 are coupled together, the pin 99 depresses the check valve member 120to an open position retracted from the annular seat 118 so that returnvapor is free to be sucked through the passage 135 by the vacuum pump.

As shown in FIG. 2, when the coupling sections 12 and 14 separate, undera breakaway condition, the tubular valve members 55 and 110 close, andthe check valve member 120 closes against the annular resilient gasketforming the seat 118. As a result of the upstream position of the checkvalve member 120 relative to the annular seat 118 within the tubularvalve member 110, the continued suction within the vapor return passage135 from the vacuum pump, is effective to pull the check valve member120 tighter against the annular seat 118 to insure that no air is suckedpast the check valve member 120 and into the vapor return passage andsystem.

Referring to FIG. 6, a coaxial breakaway coupling 150 is constructedsubstantially the same as the coupling 10 except with a shorter length.Accordingly, the same reference numbers are used to identify the samecorresponding parts or components. In order to obtain a shorter length,the compression springs 59 and 115 are replaced by compression springs152 and 154, respectively, which extend around the corresponding supporttubes 48 and 82 instead of within the support tubes for urging thetubular valve members 55 and 110 towards their closed positions.

The coaxial breakaway coupling 150 is integrated with a 45° swivelconnection or coupling 160. In place of the tubular fitting 21, a 45°tubular fitting 162 has an end portion 164 which is threaded onto theend portion 18 of the valve body 16 and is secured by a set screw 166.The fitting 162 has an opposite cylindrical end portion 168 whichrotatably supports a surrounding end portion of a 45° tubular fitting172 which has a cylindrical end portion 174. A cylindrical metal wearbushing 177 is confined within an external groove within the end portion168 of the fitting 162 and engages the fitting 172, and a resilientO-ring 179 forms a fluid-tight seal between the fittings 162 and 172. Aset of opposing annular grooves are formed within the fittings 162 and172 and have a tangential inlet for receiving an elongated flexiblenylon cord 182 or a continuous series of ball bearings for securing thefittings 162 and 172 together.

A tubular hexagonal nut 184 is mounted on the end portion 174 of thefitting 172 and is retained for relative rotation by a retaining ring187. A resilient O-ring 189 is carried by an external groove within thenut 184 and forms a fluid-tight seal between the nut and the inlet endof a fuel dispensing nozzle (not shown). Another resilient O-ring 191forms a fluid-tight seal between the fitting 172 and the nut 184.

A 45° center support tube 194 is molded of a rigid plastics materialthat includes a set of axially spaced and outwardly projectingperipheral flanges 197 and 198 which support the tube 194 concentricallywithin the tubular valve body 16 in the same manner as the support tube48 is supported within the valve body 16 by the flange 49.Circumferentially spaced arcuate slots or passages 199 are formed withinthe flanges 197 and 198 to form extensions of the liquid fuel supplypassage 138. The angular support tube 194 forms an extension of thevapor return passage 135 and rotably supports one end portion of a 45°tube 204 which is positioned concentrically within the fitting 172 andforms a further extension of the vapor return passage 135. The tube 204is also molded of a rigid plastics material and includes an outwardlyprojecting integral flange 206 with circumferentially spaced arcuateslots or passages 207 forming an extension of the fuel supply passage138. A pair of spring retaining rings 209 secure the flange 206 andcenter tube 204 within the fitting 172, and the outer end portion of thetube 204 carries a resilient O-ring 211 for forming a fluid-tight sealwith a surrounding tube within the dispensing nozzle and to form acontinuation of the vapor return passage 135.

From the drawings and the above description, it is apparent that acoaxial breakaway coupling 10 or 150 constructed in accordance with thepresent invention provides novel features and advantages and may also beintegrated with a swivel coupling 160 to provide additional advantages.For example, the coaxial breakaway coupling 10 or 150 is easy andeconomical to produce and provides for automatically closing the liquidfuel supply passage in both coupling sections 12 and 14 and forautomatically closing the vapor return passage within the section 14 inthe event the sections of the coupling are separated in response to apredetermined tension force on the coaxial fuel supply nozzle andflexible coaxial hose. In addition, the continued suction within thevapor return passage 135 within the coupling section 14 pulls the checkvalve member 120 firmly against the annular valve seat 118 to assurethat no air is sucked into the vapor recovery system when the couplingsections are separated. The mating inner surface 39 of the sleeve 32 andthe outer surface 67 of the valve body 66 also prevent relative rotationbetween the coupling sections 12 and 14 when they are coupled togetherso that the canted coil spring 76 functions to provide the desiredtension force for separation of the coupling sections and thesubstantially lower compression force for reconnecting the couplingsections. As shown in FIG. 6, the coaxial breakaway coupling 150 is alsocombined with the swivel coupling 160 to provide a compact assembly anduniversal relative movement between the coaxial fuel dispensing nozzleand the coaxial fuel supply and vapor return hose.

While the forms of coupling herein described constitute preferredembodiments of the invention, it is to be understood that the inventionis not limited to these precise forms of coupling, and that changes maybe made therein without departing from the scope and spirit of theinvention as defined in the appended claims.

The invention having thus been described, the following is claimed:
 1. Abreakaway coupling for use with a flexible coaxial fuel supply hosedefining a vapor return passage and a liquid fuel supply passage, saidcoupling comprising a first tubular valve body and a second tubularvalve body disposed with a common center axis, means for releasablyconnecting said valve bodies and providing for movement of said valvebodies from a connected position to a disconnected position in responseto an axial tension force, each of said valve bodies having an axiallyextending support tube defining therein an inner passage and cooperatingwith the surrounding said valve body to define therebetween an axiallyextending outer passage, a tubular valve member supported by each ofsaid support tubes for axial movement, each of said valve bodiesincluding means forming an annular valve seat within the correspondingsaid passage, means for moving each of said valve members axially on thecorresponding said support tube from a closed position engaging thecorresponding said valve seat to an open position retracted axially fromsaid valve seat in response to movement of said valve bodies from saiddisconnected position to said connected position, spring means forurging each of said valve members towards said closed position, a swivelcoupling including a set of angular fittings, means connecting saidfittings for relative rotation on an axis forming an acute angle withsaid center axis, one of said fittings connected to said first tubularvalve body, said support tube within said first valve body including anangular extension tube within the center of said one fitting anddefining a continuation of the corresponding said passage, and a centertube within the other said fitting and having an end portion rotatablyconnected to said extension tube.
 2. A coupling as defined in claim Iwherein said support tube and extension tube and said center tube areformed of a rigid plastics material, and each of said support tube andsaid center tube includes an integral outwardly projecting portiondefining circumferentially spaced passages.
 3. A coupling as defined inclaim 1 wherein each of said support tubes includes an outwardlyprojecting portion within said outer passage, and said flange defines aplurality of arcuate passages providing for the flow of fluid.
 4. Acoupling as defined in claim 1 wherein said means for moving saidtubular valve members comprise interfitting tubular end portions on saidvalve members, and means forming a fluid-tight seal between said tubularend portions.
 5. A coupling as defined in claim 1 wherein said means forreleasably connecting said valve bodies comprise a set of opposingannular grooves within said valve bodies, and an annular canted coilspring within said grooves.
 6. A coupling as defined in claim 1 whereinsaid first tubular valve body includes a tubular sleeve surrounding saidvalve body and having a non-cylindrical inner surface, and said secondvalve body has a mating non-cylindrical outer surface engaging saidinner surface and preventing relative rotation between said valve bodieson said center axis.
 7. A breakaway coupling for use with a flexiblecoaxial fuel supply hose defining a vapor return passage surrounded by aliquid fuel supply passage, said coupling comprising a first tubularvalve body and a second tubular valve body disposed with a common centeraxis, means for releasably connecting said valve bodies and providingfor movement of said valve bodies from a connected position to adisconnected position in response to an axial tension force, each ofsaid valve bodies having an axially extending support tube definingtherein an inner vapor return passage and cooperating with thesurrounding said valve body to define therebetween an axially extendingouter liquid fuel supply passage, a tubular valve member supported byeach of said support tubes for axial movement, each of said valve bodiesincluding means forming an annular valve seat within the correspondingfuel supply passage, spring means for moving each of said valve membersaxially on the corresponding said support tube from an open positionretracted axially from said valve seat to a closed position engaging thecorresponding said valve seat in response to movement of said valvebodies between said connected position to said disconnected position, atleast one of said tubular valve members including means forming anannular check valve seat within the corresponding said vapor returnpassage, a check valve member supported for axial movement within saidvapor return passage of said one valve member upstream of said valveseat with respect to the flow of vapor, spring means for urging each ofsaid check valve member towards said check valve seat, means supportedby said support tube within said one valve member for holding said checkvalve member in an open position spaced from said check valve seat whensaid valve bodies are in said connected position, said check valvemember being pulled to a closed position against said check valve seatin response to suction within said vapor return passage downstream ofsaid check valve seat when said valve bodies are in said disconnectedposition, a swivel coupling including a set of angular fittings, meansconnecting said fittings for relative rotation on an axis forming anangle with said center axis, one of said fittings connected to saidfirst tubular valve body, said support tube within said first valve bodyincluding an angular extension tube within the center of said onefitting and defining a continuation of said vapor return passage, and acenter tube within the other said fitting and having an end portionrotatably connected to said extension tube.
 8. A coupling as defined inclaim 7 wherein said check valve member comprises a head portion havinga tapered annular surface for engaging said annular seat within saidvapor return passage, a valve stem extending axially upstream withinsaid vapor return passage from said head portion, and a hub memberspaced within said vapor return passage of said one valve member andsupporting said stem for axial movement.
 9. A coupling as defined inclaim 7 wherein each of said support tubes includes an outwardlyprojecting flange within said fuel supply passage, and said flangedefines a plurality of passages providing for the flow of fuel.
 10. Acoupling as defined in claim 7 wherein said means for holding said checkvalve member in said open position comprise an axially extending pinsupported within the center of said support tube and positioned toengage said check valve member when said one valve member moves axiallyon the corresponding said support tube to said open position.
 11. Acoupling as defined in claim 7 wherein said means for moving saidtubular valve members comprise interfitting tubular end portions on saidvalve members, and means forming a fluid-tight seal between said tubularend portions.
 12. A coupling as defined in claim 7 wherein said meansfor releasably connecting said valve bodies comprise a set of opposingannular grooves within said valve bodies, and an annular canted coilspring within said grooves.
 13. A coupling as defined in claim 7 whereinsaid first tubular valve body includes a tubular sleeve surrounding saidvalve body and having a non-cylindrical inner surface, and said secondvalve body has a mating non-cylindrical outer surface engaging saidinner surface and preventing relative rotation between said valve bodieson said center axis.